It is God's will that some of his children should learn this deep union with himself through the perfect flowering of natural human love in marriage. For others it is equally his will that the same perfect union should be learned through the experience of learning to lay down completely this natural and instinctive desire for marriage and parenthood, and accept the circumstances of life which deny them this experience. This instinct for love, so firmly implanted in the human heart, is the supreme way by which we learn to desire and love God himself above all else.